Throughout your dancing life, you've probably heard the same corrections over and over. The reason for the repetition? Dancers tend to make the same errors, sometimes with long term results. The following are perceived to be the worst habits—the ones that will destroy a dancer's technique—and what can be done to reverse the damage.

1. Rolling In

​To get a 180-degree first position, dancers will sometimes let their arches roll forward. But turnout is not about forcing your feet open; it's about opening up in the hips. “Turning out is an activity, not a position," says Irene Dowd, who teaches anatomy at the Juilliard School. “If we stop sustaining that movement, our feet will passively roll in." Rolling in places stress on the tendons of the feet and leads to injury because the rest of the body compensates for the imbalance when your knees can't line up over your toes.Dowd warns against using only the arch to combat rolling in. “Dancers will try to lift up their arches and pull up on the inside of the ankle," she says. This can result in the inflammation of the tendons in the ankle and lead to tendinitis, a painful overuse injury that's common in dancers. Feet should be solid in three areas: the heel, the ball of the big toe, and the ball of the little toe. Imagine how your weight is being transferred from above, through the body and down the legs, rather than gripping the foot and lifting from the arch.

2. Misaligning the spine

​Distorting the back, either by crunching the lumbar vertebrae and splaying the rib cage open or by hunching the shoulders forward and tucking the pelvis under, affects every other part of the body. Since the proper placement of the torso is the foundation of any movement, a dancer with a misaligned spine will develop other deadly technique sins. Problems can ripple all the way down to the extremities and upward to the neck and head. The core will be loose, unable to provide essential support. A pelvis that either tips back or tucks under will limit the range of motion in the hips.​We should be aware that the tailbone lengthens downward without tucking under, and the navel muscles lift upward, not inward. This opposition allows the external rotator muscles to be actively engaged at the top of the thigh.

3. Clenching the toes

​Clenching, curling, knuckling—no matter what it's called, this condition hampers a dancer's ability to articulate the feet. Clenched toes also make the feet an unstable platform to stand on, creating problems for the rest of the body. The muscles and tendons of the foot, knee, and ankle must work together to perform a relevé or jump. Clenched toes will place unwanted stress on the joints of the legs, leading to imbalance and overuse injuries. On pointe, knuckling over can damage the bones and tendons of the feet.When the first joint of the toe presses down into the floor too hard, the second joint of the toe jams into the metatarsal. While seated, a dancer should prick the back of each clenched toe with a fingernail about 20 times. Sitting on a chair with the foot on the ground, she should drag it back toward the body, slowly raising it to demi-pointe with a forced arch. Another way to teach the toes to stretch out is to weave a strip of cloth over the second toe and alternate below and above successive toes, leaving it there during barrework and nondance activities.

4. Extreme hyperextension

​Hyperextended legs, in which the straightened knee naturally curves behind the thigh and calf muscles, are prized in the world of extreme ballet bodies. Dancers with extreme hyperextension must take special care. The hyperextended dancer tends to have weak external rotator muscles, so the legs are more prone to collapse in on themselves when landing from a jump, letting the body weight fall on the knees. This can result in damage to the joints that maintain the alignment of the leg, including twisted knees and sprained ankles. Even if the dancer understands how to avoid giving in to her hyperextension, she has to learn how to express herself fully while restraining her legs.The dancer must think of lengthening rather than straightening or locking the knee, even if it feels slightly bent. She must develop a heightened awareness of the turnout muscles from the top of the thigh down to the calf. The muscles must be activated to not allow the dancer to give in to the hyperextension. Somatic practices such as Pilates can help to strengthen those stabilizing turnout muscles. Dancers should stand with the heels together in first position and never be allowed to press back into that knee joint. To do this, the quadriceps must remain soft. As soon as you grip, it pulls that kneecap back dangerously.